From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Sat, 16 Jan 2010 01:01:18 +0000 (-0800)
Subject: page allocator: update NR_FREE_PAGES only when necessary
X-Git-Tag: firefly_0821_release~11625^2~323
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c91ab0438c6700e4be078d64cfb01879986e3bde;p=firefly-linux-kernel-4.4.55.git

page allocator: update NR_FREE_PAGES only when necessary

commit 6ccf80eb15ccaca4d3f1ab5162b9ded5eecd9971 upstream.

commit f2260e6b (page allocator: update NR_FREE_PAGES only as necessary)
made one minor regression.  if __rmqueue() was failed, NR_FREE_PAGES stat
go wrong.  this patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reported-by: Huang Shijie <shijie8@gmail.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2bc2ac63f41e..3a78e2e864e8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1225,10 +1225,10 @@ again:
 		}
 		spin_lock_irqsave(&zone->lock, flags);
 		page = __rmqueue(zone, order, migratetype);
-		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
 		spin_unlock(&zone->lock);
 		if (!page)
 			goto failed;
+		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
 	}
 
 	__count_zone_vm_events(PGALLOC, zone, 1 << order);